Abstract [en]

The bachelor thesis was performed at SP-Food and Bioscience (formerly SIK-Institutet för Livsmedel och Bioteknik) as part of the project DynahMat (Dynamisk Hållbarhetsdatum för Minimerat Svinn). The purpose of the study was to examine how the growth of LAB (lactic acid bacteria) was predicted by three predicative models compared to the microbial growth of LAB in naturally contaminated MA-packed cured ham.The growth of LAB in the cured ham was studied at three storage temperatures (4, 8 and 12 °C) and results showed that the spoilage of ham occurred faster at higher temperatures. The three predicative models that were used were models developed by Kreyenschmidt et al. (2010), Mataragas et al. (2006) and Devlieghere et al. (1998, 1999). The predictive models was validated by calculating accuracy and bias factors and the results showed that the models were applicable for predicting the growth of LAB.The different species of LAB in the cured ham was identified at the end of the storage time and the identification showed that the dominant species of LAB were Lactobacillus curvatus at 4 ̊C and Lactobacillus sakei at 8 and 12 ̊C.Experiment where L. monocytogenes was inoculated into the product was performed to examine its growth under the influence of LAB. The growth rate of L. monocytogenes was slow and that probably depended on the production of bacteriocins by LAB or competition for nutrients. The growth of L. monocytogenes was calculated with the FSSP and the results showed that the growth was affected by the presence of LAB.